DESCRIPTION: This is an application to continue a 23-year study of eukaryotic DNA polymerases, which originally focused on human polymerase alpha, but now also involves polymerase delta, and their functions in chromosomal DNA replication in vivo. Previous work with DNA polymerase alpha has involved in-depth analysis of the functions of active site residues in every aspect of polymerase function. A central feature of new work will be to test the hypothesis that mutations in genes that play a critical role in DNA replication can be an early event on tumorigenesis and a source of genetic instability observed in cancer cells. The investigators will initially test the mutational effect of altered forms of pol alpha and delta using fission yeast as the model. The progression of alterations in growth properties over generations will be examined. The work will then be developed in human cells and ultimately in an animal model. In another area, they have shown that pol alpha can interact with SV 40T antigen, BPV E1, and HSV UL9 as part of the process of initiation of viral replication. Experiments are proposed to analyze the interaction of pol alpha with the E1 and E2 replication proteins of HPV-11.